A headrest prevents among other things in the case of a rear end collision that the head of a vehicle occupant is catapulted rearwards relative to the vehicle. It is usually the case that headrests are insertable and height-adjustable in the backrest. In addition headrests also exist which are configured as an elongated, fixed part of the backrest of the vehicle seat. In the case of headrests currently available in vehicles, irrespective of whether the headrests are adjustable or non-adjustable, the nape of the neck of the vehicle occupant is exposed to high loads during a rear end collision because the distance of the head from the headrest, despite the pad of the back on the backrest, may be relatively large (up to 160 mm).
To relieve these loads it has already been proposed to accommodate a small gas bag in the headrest. In a crash situation, an inflator, controlled via a sensor, is activated which inflates the gas bag within a few milliseconds. Since, however, the spacing of the head from the gas bag may differ very appreciably, a very short head-to-headrest spacing, for instance, would even bump the head from the gas bag, representing an undesirable load.
Means have also been proposed which by spring storage energy or pyrotechnically in a crash situation keep track of support for the head via a corresponding activation means such that the means instantly halts in the current position in the case of head contact. However, no satisfactory solution has been found for transmitting the force to the head support.